The present invention relates to a textile yarn slashing system of the type wherein a sheet of parallel running yarns are passed through a size bath for application thereto of sizing that facilitates handling of the yarn in subsequent textile processing procedures.
Slashing systems are conventionally used for applying size to textile yarns to lubricate the surface of the yarns and to reduce surface hairiness, thereby facilitating handling of the yarn and reducing wear of machine parts in subsequent processing of the yarn into fabric. In such slashing systems, sheets of separate individual yarns are trained from rolls of yarn mounted on creels over rollers to a size bath and down into the size bath under a submerged roller and then up through nip rollers and over to other rollers for feeding through a drying chamber from which the yarns are wound, such as, for example, on warp beams. Conventionally, the yarns are dry when they are fed to the size bath and the dry yarns take up size into the interior so that sufficient size must be applied to allow for the take-up while providing full surface application. While sizing material itself is relatively inexpensive, the amount of size that is applied results in a significant cost factor.
Attempts have been made in the past to reduce the cost of size applied by reducing or controlling the amount of size applied. One heretofore commercially unsuccessful attempt has been to pre-wet the yarn to reduce the take up of size into the interior of the yarn while distributing the size over the entire surface of the yarn. An example of this involves passing the yarn through a bath of water and then through nip rolls to reduce the water content. However, nip rolls cannot reduce the water content sufficiently, leaving the yarn too wet for uniform and sufficient application of size.
Another pre-wetting system that has been attempted is to spray water on the yarn before it passes into the slasher. This also has not been successful because the atomized water particles do not spread evenly over the surface of the yarn, resulting in an uneven pick-up of size.
Yet another system that has been tried is the use of kiss rolls, that pick up water in a bath in which the roll is partially submerged and applies the picked up water from the roll onto the surface of the yarn. However, due to the high production speed necessary for practical commercial operation of slashers, there is not sufficient time for the water to wick from the surface to which it has been applied over the entire yarn surface in the short distance traveled by the yarn from the kiss roll to the size bath.
By the present invention, yarns advancing through a textile slashing system are pre-wet sufficiently to reduce the amount of size pickup by the yarns need to properly condition the yarns for subsequent processing, thereby resulting in a significant saving in the cost of size. This is accomplished by passing the yarn through a foam applicator prior to entry into the size box.
The foam applicator of the present invention has a slot extending lengthwise transversely across and facing one surface of the sheet of yarns for delivery of foam thereto. The open extent of the slot in the direction of yarn advance is relatively wide to extend the exposure of the sheet of yarns to the foam in the slot. Preferably, the applicator applies the foam under pressure so that the foam is forced through the sheet of yarns and onto the surface opposite the surface facing the slot.
In the preferred form of the applicator, the slot extends across and faces one surface of the sheet of yarns and a holddown member opposes and covers the slot for passage of the sheet of yarns therebetween and to define with the slot a foam pressure chamber. Preferably, the holddown member is formed of resilient material that is compressed by the pressurized foam to provide a space for the foam on the opposite side of the sheet of yarns from the slot. Also preferably, the slot is relatively wide to facilitate the extent of compression of the resilient holddown member to assure a space for proper foam application to all the surfaces of the yarn.
In an alternative arrangement, two foam applicators can be provided in sequence, one facing one surface of the sheet of yarns and the other facing the other surface.
An alternate feature of the present invention is the provision in an applicator for applying foam material to a traveling substrate of a sheet of flexible material covering a resilient holddown member that faces an applicator slot, with the covering sheet being advanceable from a supply to replace worn covering material with unworn covering material during operation of the applicator. The holddown member is compressible and, when used with a pressure applicator is compressed by the pressurized foam to provide a space opposite the slot and through which the substrate travels.
Yet another feature of the present invention is an applicator for applying foam material to a traveling sheet of individual aligned strands, such as the sheet of yarns in a textile yarn slashing system, of a plurality of parallel tubes containing foam and through which the strands of sheets of strands advance. Preferably there are openings adjacent the upstream ends of the tubes through which foam is introduced into the tubes and, when the applicator is a pressure applicator, foam seals are provided at the upstream and downstream ends of the tubes.
The present invention also includes an applicator flushing feature in which an applicator for applying foam material to a traveling substrate, such as sheets of yarn in a textile yarn slashing system, has a main foam passage through which foam is supplied to the substrate and a by-pass passage through which foam may be discharged for flushing of the applicator. A normally open valve is disposed in the main passage downstream from the by-pass passage and is closeable during flushing. A normally closed valve in the by-pass passage is closed during foam application through the main passage and is openable during flushing. In the preferred embodiment, these valves are inflatable bladders that are inflated to extend across the respective passages to close the passages.
Further, the present invention includes an end seal feature whereby end seals are provided in an applicator for applying foam material to a traveling substrate, where the applicator has a slotted member with a slot facing one surface of the traveling substrate and extending thereacross and has a passage having straight sides adjacent the slot for delivery of foam therethrough to the slot. An adjustable end seal member is disposed in the straight sided passage and has flat side surfaces of rigid material disposed in sealing relation to the straight sides of the passage and have resilient interior material urging the side surfaces into sealing engagement with the passage straight sides. In the preferred embodiment, the seal member includes a rigid core having sides extending generally parallel with the passage, a layer of resilient interior material secured to each side of the core and rigid material side surfaces secured to the resilient layers. Alternatively, the resilient interior material may be the core with a layer of rigid material secured to each side of the core and forming the flat side surfaces thereon.
In a further alternative embodiment the foam applied to the yarns by the applicator contains sizing material in a sufficient amount to properly condition the yarn for subsequent processing.